[turbofan] Enable tail calls for %_CallFunction.

src/compiler/js-operator.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_JS_OPERATOR_H_
 #define V8_COMPILER_JS_OPERATOR_H_
 
 #include "src/runtime/runtime.h"
 #include "src/unique.h"
 
@@ skipping 27 matching lines @@
  private:
   const MaybeHandle<TypeFeedbackVector> vector_;
   const FeedbackVectorICSlot slot_;
 };
 
 bool operator==(VectorSlotPair const&, VectorSlotPair const&);
 bool operator!=(VectorSlotPair const&, VectorSlotPair const&);
 
 size_t hash_value(VectorSlotPair const&);
 
+enum TailCallMode { NO_TAIL_CALLS, ALLOW_TAIL_CALLS };
 
 // Defines the arity and the call flags for a JavaScript function call. This is
 // used as a parameter by JSCallFunction operators.
 class CallFunctionParameters final {
  public:
   CallFunctionParameters(size_t arity, CallFunctionFlags flags,
                          LanguageMode language_mode,
-                         VectorSlotPair const& feedback)
+                         VectorSlotPair const& feedback,
+                         TailCallMode tail_call_mode)
       : bit_field_(ArityField::encode(arity) | FlagsField::encode(flags) |
                    LanguageModeField::encode(language_mode)),
-        feedback_(feedback) {}
+        feedback_(feedback),
+        tail_call_mode_(tail_call_mode) {}
 
   size_t arity() const { return ArityField::decode(bit_field_); }
   CallFunctionFlags flags() const { return FlagsField::decode(bit_field_); }
   LanguageMode language_mode() const {
     return LanguageModeField::decode(bit_field_);
   }
   VectorSlotPair const& feedback() const { return feedback_; }
 
   bool operator==(CallFunctionParameters const& that) const {
     return this->bit_field_ == that.bit_field_ &&
            this->feedback_ == that.feedback_;
   }
   bool operator!=(CallFunctionParameters const& that) const {
     return !(*this == that);
   }
 
+  bool AllowTailCalls() const { return tail_call_mode_ == ALLOW_TAIL_CALLS; }
+
  private:
   friend size_t hash_value(CallFunctionParameters const& p) {
     return base::hash_combine(p.bit_field_, p.feedback_);
   }
 
   typedef BitField<size_t, 0, 28> ArityField;
   typedef BitField<CallFunctionFlags, 28, 2> FlagsField;
   typedef BitField<LanguageMode, 30, 2> LanguageModeField;
 
   const uint32_t bit_field_;
   const VectorSlotPair feedback_;
+  bool tail_call_mode_;
 };
 
 size_t hash_value(CallFunctionParameters const&);
 
 std::ostream& operator<<(std::ostream&, CallFunctionParameters const&);
 
 const CallFunctionParameters& CallFunctionParametersOf(const Operator* op);
 
 
 // Defines the arity and the ID for a runtime function call. This is used as a
@@ skipping 312 matching lines @@
   const Operator* Yield();
 
   const Operator* Create();
   const Operator* CreateClosure(Handle<SharedFunctionInfo> shared_info,
                                 PretenureFlag pretenure);
   const Operator* CreateLiteralArray(int literal_flags);
   const Operator* CreateLiteralObject(int literal_flags);
 
   const Operator* CallFunction(
       size_t arity, CallFunctionFlags flags, LanguageMode language_mode,
-      VectorSlotPair const& feedback = VectorSlotPair());
+      VectorSlotPair const& feedback = VectorSlotPair(),
+      TailCallMode tail_call_mode = NO_TAIL_CALLS);
   const Operator* CallRuntime(Runtime::FunctionId id, size_t arity);
 
   const Operator* CallConstruct(int arguments);
 
   const Operator* LoadProperty(const VectorSlotPair& feedback,
                                LanguageMode language_mode);
   const Operator* LoadNamed(const Unique<Name>& name,
                             const VectorSlotPair& feedback,
                             LanguageMode language_mode);
 
@@ skipping 50 matching lines @@
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(JSOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_JS_OPERATOR_H_